This invention relates to diathermy apparatus, and more particularly to a diathermy hand piece in which at least the radio frequency generating portion of the power supply is carried within the hand piece so as to be in close proximity to the electrode working tips or electrode.
More generally, diathermy is a medical treatment in which heat is produced internally within the tissue of the patient by exposing the tissue to a high frequency oscillatory electrical current via a pair of energized electrodes or the like. The principles of diathermy medical treatment are typically utilized for electrocoagulation in which a mono- or bi-polar coagulator or forceps is used for hemostasis. By utilizing bi-polar coagulators, pinpoint hemostasis of tiny bleeders in the operating field is possible with minimal effects on surrounding tissue. Since thermal heat is not used for diathermy cauterization purposes, diathermy coagulation is usable in a wet operating field, whether used in conjunction with a saline irrigation agent or whether the operating field is bloody. The advent of such bi-polar diathermy coagulator apparatus has led to many medical advances in neurological and microsurgical techniques because it is now possible to effectively restrict the area of tissue damage. It will be understood that the general principle of diathermy coagulation is that by heating the tissue, the tissue proteins are coagulated thus stopping bleeding. By using carefully controlled diathermy coagulator apparatus, charring and other excessive heating of the tissue surrounding the bleeders is minimized.
Several years ago, upon the introduction of diathermy techniques, radio frequency generators were used to energized the coagulators. Typically, these radio frequency generators were quite large in size and were located remotely from the mono-polar or bi-polar forceps or hand piece. The radio frequency energy generated by the radio frequency generator was carried to the hand piece by elongate electrical leads or the like. In many early diathermy instruments, a quenched spark gap transmitter was utilized as the radio frequency generator. The wave forms generated by such quenched spark gap power supplies were of fairly high voltage which resulted in relatively deep tissue penetration and were intermittent such that little heat was generated and such that each cycle produced only a small degree of coagulation. Thus, as compared to heated wire cauterization apparatus, a uniform heat at a predetermined tissue depth produced less heat with more coagulation, provided more control for the surgeon, and resulted in less charring and other damage to the surrounding tissue.
As mentioned, the radio frequency generators of prior art diathermy apparatus were located remotely from the electrodes utilized by the surgeon and the electrodes were connected to the radio frequency generator by relatively long electrical lead wires. Because of the large size of the radio frequency generator, it was often difficult to find space for the radio frequency generator in a crowded operating room. Also, because of the large size of the radio frequency generator and the type of equipment (i.e., an oscillatory radio frequency source), it was difficult to sterilize the radio frequency generator without causing damage to the generator or without applying harmful chemicals. Also, by energizing the electrodes with high frequency radio frequency energy via long lead lines, various capacitive loads were impressed on the radio frequency output which in turn required the radio frequency generator to emit more power than was necessary for diathermy treatment of the patient. This inefficiency in radio frequency generators has resulted in increased danger to the patient and in increased radio frequency interference with other electronical equipment now commonly utilized in the modern operating room. Further, many prior art diathermy coagulators, referred to as mono-polar coagulators, required that the patient be grounded by a suitable grounding pad. Also, as was conventional, prior art diathermy coagulators were typically activated by means of a foot switch actuated by the surgeon. It was found that in various microsurgery applications, the requirement of a foot switch was awkward and often required the surgeon to change his body position from a desired position while performing neurological or microsurgery.